Page 55 - Handbook of Adhesion Promoters

48 Mechanisms of Adhesion Loss

Figure 3.3. Layers would squeeze each other because of interlayer expansion discrepancy and cause cracks. A
sketch of stress and crack formation was displayed in part (a). A hole (in the green square) was found during wet-
ting (b) and drying (c). [Adapted, by permission, from He, X; Xu, M; Zhang, HH; Zhang, B; Su, B, J. Archeol.
Sci., 42, 194-200, 2014.]

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having MoO and Cr adhesive interlayers below the device cathode. An oxide layer
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forms at the cathode interface to the organic and a delamination is prevented.
The electrochemical impedance spectroscopy was used to quantify the effect of
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moisture on the interlayer adhesion of automotive coatings. A strong sensitivity of the
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interlayer impedance to the outer air humidity was established. The water accumulation
in the interlayer is possible which may lead to the adhesion loss and delamination between
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the coating layers.
Various kinds of conservation materials (PVA and acrylic acid) and techniques
(adhesion, consolidation, and surface coating) have been used to extend the lifetime of
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wall paintings in the Mogao Grottoes. The layers of wall paintings have different physical
properties, such as thermal and moisture expansions, which may be altered when paintings
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are penetrated by the conservation materials. These differences in properties may cause
stress between the layers in the paintings caused by the change of environmental factors
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and lead to deterioration of wall paintings (Figure 3.3). The humidity change was more
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important for wall painting deterioration than the temperature change.
The stress field produced leads to either cracks or delamination of the applied layer
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when the scratch tool is applied to the material surface. In multilayer coatings, the whole
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system plays a role in the scratch performance of the coating (not only the top layer).
The tribological performance of implant materials depends on the type of materials
used, contact stresses, lubricants and clearance, surface hardness and roughness, type of
articulation due to motion, the number of cycles, solution particle count and distribution,
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and tribocorrosion. The synergistic interactions between wear and corrosion determine
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the overall success of implant material.
Ethylene vinyl acetate copolymer is used as embedding material of crystalline sili-
con photovoltaics. It plays a role of the electrical insulation and protection of cells against
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mechanical and environmental stresses. EVA degradation during environmental expo-
sure may cause adhesion loss, delamination, and yellowing, resulting in a drop of module